linux/drivers/pci/access.c
Matthew R. Ochs 4f69bd16df PCI: Increase VPD access timeout to 125ms
The PCI core uses a fixed 50ms timeout when waiting for VPD accesses to
complete.  When an access does not complete within this period, a warning
is logged and an error returned to the caller.

While this default timeout is valid for most hardware, some devices can
experience longer access delays under certain circumstances.  For example,
one of the IBM CXL Flash devices can take up to ~120ms in a worst-case
scenario.  These types of devices can benefit from an extended timeout.

To support devices with a longer access delay, increase the timeout in
pci_vpd_wait() to 125ms.  The PCI specification is silent with respect to
VPD delays, therefore there is no concern for violating a threshold.

Tested-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
2017-02-03 11:16:30 -06:00

892 lines
21 KiB
C

#include <linux/delay.h>
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/wait.h>
#include "pci.h"
/*
* This interrupt-safe spinlock protects all accesses to PCI
* configuration space.
*/
DEFINE_RAW_SPINLOCK(pci_lock);
/*
* Wrappers for all PCI configuration access functions. They just check
* alignment, do locking and call the low-level functions pointed to
* by pci_dev->ops.
*/
#define PCI_byte_BAD 0
#define PCI_word_BAD (pos & 1)
#define PCI_dword_BAD (pos & 3)
#define PCI_OP_READ(size, type, len) \
int pci_bus_read_config_##size \
(struct pci_bus *bus, unsigned int devfn, int pos, type *value) \
{ \
int res; \
unsigned long flags; \
u32 data = 0; \
if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
raw_spin_lock_irqsave(&pci_lock, flags); \
res = bus->ops->read(bus, devfn, pos, len, &data); \
*value = (type)data; \
raw_spin_unlock_irqrestore(&pci_lock, flags); \
return res; \
}
#define PCI_OP_WRITE(size, type, len) \
int pci_bus_write_config_##size \
(struct pci_bus *bus, unsigned int devfn, int pos, type value) \
{ \
int res; \
unsigned long flags; \
if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER; \
raw_spin_lock_irqsave(&pci_lock, flags); \
res = bus->ops->write(bus, devfn, pos, len, value); \
raw_spin_unlock_irqrestore(&pci_lock, flags); \
return res; \
}
PCI_OP_READ(byte, u8, 1)
PCI_OP_READ(word, u16, 2)
PCI_OP_READ(dword, u32, 4)
PCI_OP_WRITE(byte, u8, 1)
PCI_OP_WRITE(word, u16, 2)
PCI_OP_WRITE(dword, u32, 4)
EXPORT_SYMBOL(pci_bus_read_config_byte);
EXPORT_SYMBOL(pci_bus_read_config_word);
EXPORT_SYMBOL(pci_bus_read_config_dword);
EXPORT_SYMBOL(pci_bus_write_config_byte);
EXPORT_SYMBOL(pci_bus_write_config_word);
EXPORT_SYMBOL(pci_bus_write_config_dword);
int pci_generic_config_read(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 *val)
{
void __iomem *addr;
addr = bus->ops->map_bus(bus, devfn, where);
if (!addr) {
*val = ~0;
return PCIBIOS_DEVICE_NOT_FOUND;
}
if (size == 1)
*val = readb(addr);
else if (size == 2)
*val = readw(addr);
else
*val = readl(addr);
return PCIBIOS_SUCCESSFUL;
}
EXPORT_SYMBOL_GPL(pci_generic_config_read);
int pci_generic_config_write(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 val)
{
void __iomem *addr;
addr = bus->ops->map_bus(bus, devfn, where);
if (!addr)
return PCIBIOS_DEVICE_NOT_FOUND;
if (size == 1)
writeb(val, addr);
else if (size == 2)
writew(val, addr);
else
writel(val, addr);
return PCIBIOS_SUCCESSFUL;
}
EXPORT_SYMBOL_GPL(pci_generic_config_write);
int pci_generic_config_read32(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 *val)
{
void __iomem *addr;
addr = bus->ops->map_bus(bus, devfn, where & ~0x3);
if (!addr) {
*val = ~0;
return PCIBIOS_DEVICE_NOT_FOUND;
}
*val = readl(addr);
if (size <= 2)
*val = (*val >> (8 * (where & 3))) & ((1 << (size * 8)) - 1);
return PCIBIOS_SUCCESSFUL;
}
EXPORT_SYMBOL_GPL(pci_generic_config_read32);
int pci_generic_config_write32(struct pci_bus *bus, unsigned int devfn,
int where, int size, u32 val)
{
void __iomem *addr;
u32 mask, tmp;
addr = bus->ops->map_bus(bus, devfn, where & ~0x3);
if (!addr)
return PCIBIOS_DEVICE_NOT_FOUND;
if (size == 4) {
writel(val, addr);
return PCIBIOS_SUCCESSFUL;
}
/*
* In general, hardware that supports only 32-bit writes on PCI is
* not spec-compliant. For example, software may perform a 16-bit
* write. If the hardware only supports 32-bit accesses, we must
* do a 32-bit read, merge in the 16 bits we intend to write,
* followed by a 32-bit write. If the 16 bits we *don't* intend to
* write happen to have any RW1C (write-one-to-clear) bits set, we
* just inadvertently cleared something we shouldn't have.
*/
dev_warn_ratelimited(&bus->dev, "%d-byte config write to %04x:%02x:%02x.%d offset %#x may corrupt adjacent RW1C bits\n",
size, pci_domain_nr(bus), bus->number,
PCI_SLOT(devfn), PCI_FUNC(devfn), where);
mask = ~(((1 << (size * 8)) - 1) << ((where & 0x3) * 8));
tmp = readl(addr) & mask;
tmp |= val << ((where & 0x3) * 8);
writel(tmp, addr);
return PCIBIOS_SUCCESSFUL;
}
EXPORT_SYMBOL_GPL(pci_generic_config_write32);
/**
* pci_bus_set_ops - Set raw operations of pci bus
* @bus: pci bus struct
* @ops: new raw operations
*
* Return previous raw operations
*/
struct pci_ops *pci_bus_set_ops(struct pci_bus *bus, struct pci_ops *ops)
{
struct pci_ops *old_ops;
unsigned long flags;
raw_spin_lock_irqsave(&pci_lock, flags);
old_ops = bus->ops;
bus->ops = ops;
raw_spin_unlock_irqrestore(&pci_lock, flags);
return old_ops;
}
EXPORT_SYMBOL(pci_bus_set_ops);
/*
* The following routines are to prevent the user from accessing PCI config
* space when it's unsafe to do so. Some devices require this during BIST and
* we're required to prevent it during D-state transitions.
*
* We have a bit per device to indicate it's blocked and a global wait queue
* for callers to sleep on until devices are unblocked.
*/
static DECLARE_WAIT_QUEUE_HEAD(pci_cfg_wait);
static noinline void pci_wait_cfg(struct pci_dev *dev)
{
DECLARE_WAITQUEUE(wait, current);
__add_wait_queue(&pci_cfg_wait, &wait);
do {
set_current_state(TASK_UNINTERRUPTIBLE);
raw_spin_unlock_irq(&pci_lock);
schedule();
raw_spin_lock_irq(&pci_lock);
} while (dev->block_cfg_access);
__remove_wait_queue(&pci_cfg_wait, &wait);
}
/* Returns 0 on success, negative values indicate error. */
#define PCI_USER_READ_CONFIG(size, type) \
int pci_user_read_config_##size \
(struct pci_dev *dev, int pos, type *val) \
{ \
int ret = PCIBIOS_SUCCESSFUL; \
u32 data = -1; \
if (PCI_##size##_BAD) \
return -EINVAL; \
raw_spin_lock_irq(&pci_lock); \
if (unlikely(dev->block_cfg_access)) \
pci_wait_cfg(dev); \
ret = dev->bus->ops->read(dev->bus, dev->devfn, \
pos, sizeof(type), &data); \
raw_spin_unlock_irq(&pci_lock); \
*val = (type)data; \
return pcibios_err_to_errno(ret); \
} \
EXPORT_SYMBOL_GPL(pci_user_read_config_##size);
/* Returns 0 on success, negative values indicate error. */
#define PCI_USER_WRITE_CONFIG(size, type) \
int pci_user_write_config_##size \
(struct pci_dev *dev, int pos, type val) \
{ \
int ret = PCIBIOS_SUCCESSFUL; \
if (PCI_##size##_BAD) \
return -EINVAL; \
raw_spin_lock_irq(&pci_lock); \
if (unlikely(dev->block_cfg_access)) \
pci_wait_cfg(dev); \
ret = dev->bus->ops->write(dev->bus, dev->devfn, \
pos, sizeof(type), val); \
raw_spin_unlock_irq(&pci_lock); \
return pcibios_err_to_errno(ret); \
} \
EXPORT_SYMBOL_GPL(pci_user_write_config_##size);
PCI_USER_READ_CONFIG(byte, u8)
PCI_USER_READ_CONFIG(word, u16)
PCI_USER_READ_CONFIG(dword, u32)
PCI_USER_WRITE_CONFIG(byte, u8)
PCI_USER_WRITE_CONFIG(word, u16)
PCI_USER_WRITE_CONFIG(dword, u32)
/* VPD access through PCI 2.2+ VPD capability */
/**
* pci_read_vpd - Read one entry from Vital Product Data
* @dev: pci device struct
* @pos: offset in vpd space
* @count: number of bytes to read
* @buf: pointer to where to store result
*/
ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf)
{
if (!dev->vpd || !dev->vpd->ops)
return -ENODEV;
return dev->vpd->ops->read(dev, pos, count, buf);
}
EXPORT_SYMBOL(pci_read_vpd);
/**
* pci_write_vpd - Write entry to Vital Product Data
* @dev: pci device struct
* @pos: offset in vpd space
* @count: number of bytes to write
* @buf: buffer containing write data
*/
ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf)
{
if (!dev->vpd || !dev->vpd->ops)
return -ENODEV;
return dev->vpd->ops->write(dev, pos, count, buf);
}
EXPORT_SYMBOL(pci_write_vpd);
/**
* pci_set_vpd_size - Set size of Vital Product Data space
* @dev: pci device struct
* @len: size of vpd space
*/
int pci_set_vpd_size(struct pci_dev *dev, size_t len)
{
if (!dev->vpd || !dev->vpd->ops)
return -ENODEV;
return dev->vpd->ops->set_size(dev, len);
}
EXPORT_SYMBOL(pci_set_vpd_size);
#define PCI_VPD_MAX_SIZE (PCI_VPD_ADDR_MASK + 1)
/**
* pci_vpd_size - determine actual size of Vital Product Data
* @dev: pci device struct
* @old_size: current assumed size, also maximum allowed size
*/
static size_t pci_vpd_size(struct pci_dev *dev, size_t old_size)
{
size_t off = 0;
unsigned char header[1+2]; /* 1 byte tag, 2 bytes length */
while (off < old_size &&
pci_read_vpd(dev, off, 1, header) == 1) {
unsigned char tag;
if (header[0] & PCI_VPD_LRDT) {
/* Large Resource Data Type Tag */
tag = pci_vpd_lrdt_tag(header);
/* Only read length from known tag items */
if ((tag == PCI_VPD_LTIN_ID_STRING) ||
(tag == PCI_VPD_LTIN_RO_DATA) ||
(tag == PCI_VPD_LTIN_RW_DATA)) {
if (pci_read_vpd(dev, off+1, 2,
&header[1]) != 2) {
dev_warn(&dev->dev,
"invalid large VPD tag %02x size at offset %zu",
tag, off + 1);
return 0;
}
off += PCI_VPD_LRDT_TAG_SIZE +
pci_vpd_lrdt_size(header);
}
} else {
/* Short Resource Data Type Tag */
off += PCI_VPD_SRDT_TAG_SIZE +
pci_vpd_srdt_size(header);
tag = pci_vpd_srdt_tag(header);
}
if (tag == PCI_VPD_STIN_END) /* End tag descriptor */
return off;
if ((tag != PCI_VPD_LTIN_ID_STRING) &&
(tag != PCI_VPD_LTIN_RO_DATA) &&
(tag != PCI_VPD_LTIN_RW_DATA)) {
dev_warn(&dev->dev,
"invalid %s VPD tag %02x at offset %zu",
(header[0] & PCI_VPD_LRDT) ? "large" : "short",
tag, off);
return 0;
}
}
return 0;
}
/*
* Wait for last operation to complete.
* This code has to spin since there is no other notification from the PCI
* hardware. Since the VPD is often implemented by serial attachment to an
* EEPROM, it may take many milliseconds to complete.
*
* Returns 0 on success, negative values indicate error.
*/
static int pci_vpd_wait(struct pci_dev *dev)
{
struct pci_vpd *vpd = dev->vpd;
unsigned long timeout = jiffies + msecs_to_jiffies(125);
unsigned long max_sleep = 16;
u16 status;
int ret;
if (!vpd->busy)
return 0;
while (time_before(jiffies, timeout)) {
ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR,
&status);
if (ret < 0)
return ret;
if ((status & PCI_VPD_ADDR_F) == vpd->flag) {
vpd->busy = 0;
return 0;
}
if (fatal_signal_pending(current))
return -EINTR;
usleep_range(10, max_sleep);
if (max_sleep < 1024)
max_sleep *= 2;
}
dev_warn(&dev->dev, "VPD access failed. This is likely a firmware bug on this device. Contact the card vendor for a firmware update\n");
return -ETIMEDOUT;
}
static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count,
void *arg)
{
struct pci_vpd *vpd = dev->vpd;
int ret;
loff_t end = pos + count;
u8 *buf = arg;
if (pos < 0)
return -EINVAL;
if (!vpd->valid) {
vpd->valid = 1;
vpd->len = pci_vpd_size(dev, vpd->len);
}
if (vpd->len == 0)
return -EIO;
if (pos > vpd->len)
return 0;
if (end > vpd->len) {
end = vpd->len;
count = end - pos;
}
if (mutex_lock_killable(&vpd->lock))
return -EINTR;
ret = pci_vpd_wait(dev);
if (ret < 0)
goto out;
while (pos < end) {
u32 val;
unsigned int i, skip;
ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
pos & ~3);
if (ret < 0)
break;
vpd->busy = 1;
vpd->flag = PCI_VPD_ADDR_F;
ret = pci_vpd_wait(dev);
if (ret < 0)
break;
ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, &val);
if (ret < 0)
break;
skip = pos & 3;
for (i = 0; i < sizeof(u32); i++) {
if (i >= skip) {
*buf++ = val;
if (++pos == end)
break;
}
val >>= 8;
}
}
out:
mutex_unlock(&vpd->lock);
return ret ? ret : count;
}
static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count,
const void *arg)
{
struct pci_vpd *vpd = dev->vpd;
const u8 *buf = arg;
loff_t end = pos + count;
int ret = 0;
if (pos < 0 || (pos & 3) || (count & 3))
return -EINVAL;
if (!vpd->valid) {
vpd->valid = 1;
vpd->len = pci_vpd_size(dev, vpd->len);
}
if (vpd->len == 0)
return -EIO;
if (end > vpd->len)
return -EINVAL;
if (mutex_lock_killable(&vpd->lock))
return -EINTR;
ret = pci_vpd_wait(dev);
if (ret < 0)
goto out;
while (pos < end) {
u32 val;
val = *buf++;
val |= *buf++ << 8;
val |= *buf++ << 16;
val |= *buf++ << 24;
ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA, val);
if (ret < 0)
break;
ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
pos | PCI_VPD_ADDR_F);
if (ret < 0)
break;
vpd->busy = 1;
vpd->flag = 0;
ret = pci_vpd_wait(dev);
if (ret < 0)
break;
pos += sizeof(u32);
}
out:
mutex_unlock(&vpd->lock);
return ret ? ret : count;
}
static int pci_vpd_set_size(struct pci_dev *dev, size_t len)
{
struct pci_vpd *vpd = dev->vpd;
if (len == 0 || len > PCI_VPD_MAX_SIZE)
return -EIO;
vpd->valid = 1;
vpd->len = len;
return 0;
}
static const struct pci_vpd_ops pci_vpd_ops = {
.read = pci_vpd_read,
.write = pci_vpd_write,
.set_size = pci_vpd_set_size,
};
static ssize_t pci_vpd_f0_read(struct pci_dev *dev, loff_t pos, size_t count,
void *arg)
{
struct pci_dev *tdev = pci_get_slot(dev->bus,
PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
ssize_t ret;
if (!tdev)
return -ENODEV;
ret = pci_read_vpd(tdev, pos, count, arg);
pci_dev_put(tdev);
return ret;
}
static ssize_t pci_vpd_f0_write(struct pci_dev *dev, loff_t pos, size_t count,
const void *arg)
{
struct pci_dev *tdev = pci_get_slot(dev->bus,
PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
ssize_t ret;
if (!tdev)
return -ENODEV;
ret = pci_write_vpd(tdev, pos, count, arg);
pci_dev_put(tdev);
return ret;
}
static int pci_vpd_f0_set_size(struct pci_dev *dev, size_t len)
{
struct pci_dev *tdev = pci_get_slot(dev->bus,
PCI_DEVFN(PCI_SLOT(dev->devfn), 0));
int ret;
if (!tdev)
return -ENODEV;
ret = pci_set_vpd_size(tdev, len);
pci_dev_put(tdev);
return ret;
}
static const struct pci_vpd_ops pci_vpd_f0_ops = {
.read = pci_vpd_f0_read,
.write = pci_vpd_f0_write,
.set_size = pci_vpd_f0_set_size,
};
int pci_vpd_init(struct pci_dev *dev)
{
struct pci_vpd *vpd;
u8 cap;
cap = pci_find_capability(dev, PCI_CAP_ID_VPD);
if (!cap)
return -ENODEV;
vpd = kzalloc(sizeof(*vpd), GFP_ATOMIC);
if (!vpd)
return -ENOMEM;
vpd->len = PCI_VPD_MAX_SIZE;
if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0)
vpd->ops = &pci_vpd_f0_ops;
else
vpd->ops = &pci_vpd_ops;
mutex_init(&vpd->lock);
vpd->cap = cap;
vpd->busy = 0;
vpd->valid = 0;
dev->vpd = vpd;
return 0;
}
void pci_vpd_release(struct pci_dev *dev)
{
kfree(dev->vpd);
}
/**
* pci_cfg_access_lock - Lock PCI config reads/writes
* @dev: pci device struct
*
* When access is locked, any userspace reads or writes to config
* space and concurrent lock requests will sleep until access is
* allowed via pci_cfg_access_unlocked again.
*/
void pci_cfg_access_lock(struct pci_dev *dev)
{
might_sleep();
raw_spin_lock_irq(&pci_lock);
if (dev->block_cfg_access)
pci_wait_cfg(dev);
dev->block_cfg_access = 1;
raw_spin_unlock_irq(&pci_lock);
}
EXPORT_SYMBOL_GPL(pci_cfg_access_lock);
/**
* pci_cfg_access_trylock - try to lock PCI config reads/writes
* @dev: pci device struct
*
* Same as pci_cfg_access_lock, but will return 0 if access is
* already locked, 1 otherwise. This function can be used from
* atomic contexts.
*/
bool pci_cfg_access_trylock(struct pci_dev *dev)
{
unsigned long flags;
bool locked = true;
raw_spin_lock_irqsave(&pci_lock, flags);
if (dev->block_cfg_access)
locked = false;
else
dev->block_cfg_access = 1;
raw_spin_unlock_irqrestore(&pci_lock, flags);
return locked;
}
EXPORT_SYMBOL_GPL(pci_cfg_access_trylock);
/**
* pci_cfg_access_unlock - Unlock PCI config reads/writes
* @dev: pci device struct
*
* This function allows PCI config accesses to resume.
*/
void pci_cfg_access_unlock(struct pci_dev *dev)
{
unsigned long flags;
raw_spin_lock_irqsave(&pci_lock, flags);
/* This indicates a problem in the caller, but we don't need
* to kill them, unlike a double-block above. */
WARN_ON(!dev->block_cfg_access);
dev->block_cfg_access = 0;
wake_up_all(&pci_cfg_wait);
raw_spin_unlock_irqrestore(&pci_lock, flags);
}
EXPORT_SYMBOL_GPL(pci_cfg_access_unlock);
static inline int pcie_cap_version(const struct pci_dev *dev)
{
return pcie_caps_reg(dev) & PCI_EXP_FLAGS_VERS;
}
static bool pcie_downstream_port(const struct pci_dev *dev)
{
int type = pci_pcie_type(dev);
return type == PCI_EXP_TYPE_ROOT_PORT ||
type == PCI_EXP_TYPE_DOWNSTREAM;
}
bool pcie_cap_has_lnkctl(const struct pci_dev *dev)
{
int type = pci_pcie_type(dev);
return type == PCI_EXP_TYPE_ENDPOINT ||
type == PCI_EXP_TYPE_LEG_END ||
type == PCI_EXP_TYPE_ROOT_PORT ||
type == PCI_EXP_TYPE_UPSTREAM ||
type == PCI_EXP_TYPE_DOWNSTREAM ||
type == PCI_EXP_TYPE_PCI_BRIDGE ||
type == PCI_EXP_TYPE_PCIE_BRIDGE;
}
static inline bool pcie_cap_has_sltctl(const struct pci_dev *dev)
{
return pcie_downstream_port(dev) &&
pcie_caps_reg(dev) & PCI_EXP_FLAGS_SLOT;
}
static inline bool pcie_cap_has_rtctl(const struct pci_dev *dev)
{
int type = pci_pcie_type(dev);
return type == PCI_EXP_TYPE_ROOT_PORT ||
type == PCI_EXP_TYPE_RC_EC;
}
static bool pcie_capability_reg_implemented(struct pci_dev *dev, int pos)
{
if (!pci_is_pcie(dev))
return false;
switch (pos) {
case PCI_EXP_FLAGS:
return true;
case PCI_EXP_DEVCAP:
case PCI_EXP_DEVCTL:
case PCI_EXP_DEVSTA:
return true;
case PCI_EXP_LNKCAP:
case PCI_EXP_LNKCTL:
case PCI_EXP_LNKSTA:
return pcie_cap_has_lnkctl(dev);
case PCI_EXP_SLTCAP:
case PCI_EXP_SLTCTL:
case PCI_EXP_SLTSTA:
return pcie_cap_has_sltctl(dev);
case PCI_EXP_RTCTL:
case PCI_EXP_RTCAP:
case PCI_EXP_RTSTA:
return pcie_cap_has_rtctl(dev);
case PCI_EXP_DEVCAP2:
case PCI_EXP_DEVCTL2:
case PCI_EXP_LNKCAP2:
case PCI_EXP_LNKCTL2:
case PCI_EXP_LNKSTA2:
return pcie_cap_version(dev) > 1;
default:
return false;
}
}
/*
* Note that these accessor functions are only for the "PCI Express
* Capability" (see PCIe spec r3.0, sec 7.8). They do not apply to the
* other "PCI Express Extended Capabilities" (AER, VC, ACS, MFVC, etc.)
*/
int pcie_capability_read_word(struct pci_dev *dev, int pos, u16 *val)
{
int ret;
*val = 0;
if (pos & 1)
return -EINVAL;
if (pcie_capability_reg_implemented(dev, pos)) {
ret = pci_read_config_word(dev, pci_pcie_cap(dev) + pos, val);
/*
* Reset *val to 0 if pci_read_config_word() fails, it may
* have been written as 0xFFFF if hardware error happens
* during pci_read_config_word().
*/
if (ret)
*val = 0;
return ret;
}
/*
* For Functions that do not implement the Slot Capabilities,
* Slot Status, and Slot Control registers, these spaces must
* be hardwired to 0b, with the exception of the Presence Detect
* State bit in the Slot Status register of Downstream Ports,
* which must be hardwired to 1b. (PCIe Base Spec 3.0, sec 7.8)
*/
if (pci_is_pcie(dev) && pcie_downstream_port(dev) &&
pos == PCI_EXP_SLTSTA)
*val = PCI_EXP_SLTSTA_PDS;
return 0;
}
EXPORT_SYMBOL(pcie_capability_read_word);
int pcie_capability_read_dword(struct pci_dev *dev, int pos, u32 *val)
{
int ret;
*val = 0;
if (pos & 3)
return -EINVAL;
if (pcie_capability_reg_implemented(dev, pos)) {
ret = pci_read_config_dword(dev, pci_pcie_cap(dev) + pos, val);
/*
* Reset *val to 0 if pci_read_config_dword() fails, it may
* have been written as 0xFFFFFFFF if hardware error happens
* during pci_read_config_dword().
*/
if (ret)
*val = 0;
return ret;
}
if (pci_is_pcie(dev) && pcie_downstream_port(dev) &&
pos == PCI_EXP_SLTSTA)
*val = PCI_EXP_SLTSTA_PDS;
return 0;
}
EXPORT_SYMBOL(pcie_capability_read_dword);
int pcie_capability_write_word(struct pci_dev *dev, int pos, u16 val)
{
if (pos & 1)
return -EINVAL;
if (!pcie_capability_reg_implemented(dev, pos))
return 0;
return pci_write_config_word(dev, pci_pcie_cap(dev) + pos, val);
}
EXPORT_SYMBOL(pcie_capability_write_word);
int pcie_capability_write_dword(struct pci_dev *dev, int pos, u32 val)
{
if (pos & 3)
return -EINVAL;
if (!pcie_capability_reg_implemented(dev, pos))
return 0;
return pci_write_config_dword(dev, pci_pcie_cap(dev) + pos, val);
}
EXPORT_SYMBOL(pcie_capability_write_dword);
int pcie_capability_clear_and_set_word(struct pci_dev *dev, int pos,
u16 clear, u16 set)
{
int ret;
u16 val;
ret = pcie_capability_read_word(dev, pos, &val);
if (!ret) {
val &= ~clear;
val |= set;
ret = pcie_capability_write_word(dev, pos, val);
}
return ret;
}
EXPORT_SYMBOL(pcie_capability_clear_and_set_word);
int pcie_capability_clear_and_set_dword(struct pci_dev *dev, int pos,
u32 clear, u32 set)
{
int ret;
u32 val;
ret = pcie_capability_read_dword(dev, pos, &val);
if (!ret) {
val &= ~clear;
val |= set;
ret = pcie_capability_write_dword(dev, pos, val);
}
return ret;
}
EXPORT_SYMBOL(pcie_capability_clear_and_set_dword);